H2O2-Induced Oxidative Dissolution of UO2 in Saline Solutions

• H2O2 is one of the oxidants responsible for driving the process of radiation-induced dissolution of spent nuclear fuel in geological repositories for spent nuclear fuel. As the groundwater composition will vary depending on geographical location as well as on the age of the repository (in relation to glacial cycles, etc.), it is important to elucidate the impact of different groundwater constituents. While several studies have addressed the impact of HCO3− and halide ions on the radiation chemistry of water in general and radiation-induced oxidative dissolution of spent nuclear fuel in particular, very few studies have addressed the impact of halide ions on the mechanism of the reaction between H2O2 and UO2. In this work, the impact of Cl−, Br− and ClO4− on the mechanism and kinetics of H2O2-induced oxidative dissolution of UO2-powder in aqueous suspensions with and without added HCO3− has been studied experimentally. The experiments reveal both ionic strength effects and specific ion effects on the kinetics of the reactions involved. These are discussed in connection to the results.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

Dissolution kinetics

Halides

Ionic strength

Uranium

Uranyl complexes

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